Fixation device for blading of a turbo-machine

ABSTRACT

A device is shown for fixing blades of a turbo-machine having a plurality of blades positioned longitudinally relative to a mounting groove. At least two blades are positioned adjacent to each other inside the mounting groove, and a mounting gap is defined between the blades. Two insertion elements constructed as collar halves can be inserted into the mounting gap, and each insertion element has a width adapted to the width of the mounting gap such that a gap space is defined between the insertion elements when they are inserted into the mounting gap. A wedge element can be inserted in the mounting gap to fix both collar halves inside the mounting groove. At least one connecting element is provided on the wedge element towards the side of a blade, and at least one of the two blades adjoining the wedge element is provided with a mating recess corresponding to the connecting element so that the wedge element and the blade are connected by a shape-mated connection.

FIELD OF THE INVENTION

[0001] The invention relates to a device for fixing blades in a turbo-machine. A plurality of blades is positioned longitudinally relative to a mounting groove, and between at least two blades positioned adjacent to each other inside the mounting groove, a mounting gap is provided, having two insertion elements constructed as collar halves that can be inserted into the mounting gap, and each of which has a width adapted to the width of the mounting gap and which enclose between themselves a gap space into which a wedge element can be inserted that can be wedged in such a way that both collar halves are fixed in a force-derived manner by means of the wedge element inside the mounting groove.

BACKGROUND OF THE INVENTION

[0002] Blades of the previously described type are related to guide blades, but in particular to rotating blades inside turbo-machines, such as, for example, the compressor or turbine stage of a gas turbine system. The following explanations relate preferably to rotating blades provided longitudinally relative to a mounting groove provided inside the rotor of a turbo-machine. The rotating blades can extend around the rotor along its circumference, and must be positioned in a suitable manner with respect to the respective flow conditions. The rotating blades must also be reliably secured against potential maladjustments during the operation of the turbo-machines, but in particular against a complete detachment from the mounting groove. The measures to be instituted with respect to the rotating blades, as described below, can also be used, however, for the guide blades integrated in the stationary housing components of turbo-machines.

[0003] The risk of a complete detachment of individual rotating blades from the respective mounting means exists if the rotating blades inserted inside the mounting grooves and attached in known manners are able to move unevenly within the respective mounting play circumferentially along the mounting groove on the rotor. Such peripheral maladjustments in a plurality of rotating blades inserted along the mounting groove may result in a significant gap being created between two adjoining rotating blades. The gap could be large enough so that a rotating blade is able to detach itself by radial twisting from the mounting groove, resulting in substantial damage to the entire turbo-machine system.

[0004] In general, known means for securing against an autonomous detachment of individual rotating blades from the mounting groove relate to the reduction of the play in circumferential direction between two adjacent blade roots within the mounting groove. After installing all rotating blades inserted into the mounting groove, as well as all whole and halved intermediate pieces, a gap is created between, for example, two adjacent rotating blades facing each other inside the mounting groove. This gap is referred to as a mounting gap, and a rotor collar is inserted into the mounting gap so that the play between the rotating blades set into the mounting groove and between the intermediate pieces is minimized.

[0005] A conventional rotor collar is described below in reference to FIGS. 2a-2 c. FIG. 2a shows a cross-section through a mounting groove 1 fabricated within a rotor 2. Two rotating blades 31, 32 are positioned immediately adjacent to each other within the mounting groove 1 (see top view according to FIG. 2c). The so-called rotor collar 4 is inserted radially between the two blades 31, 32 in the mounting groove 1 to mutually attach the blades. As illustrated in detail in FIG. 2b, the rotor collar 4 consists of two collar halves 41, 42 as well as a wedge element 43. The sides of the collar halves 41, 42, which each face towards the mounting groove 1, are appropriately designed for a force-derived and shape-mated engagement with the internal contour of the mounting groove 1. In the inserted condition within the mounting groove 1, both collar halves 41, 42 enclose a gap 5, into which the wedge element 43 can be inserted in a radial direction. In the top portion, the collar halves 41, 42 have a corresponding recess 6 (see FIG. 2b), each of which is similar to the shape of half a heart, in which the retention tabs 44 of the wedge element 43 are permanently spread according to the illustration in FIG. 2a, in order to permanently spread both collar halves 41, 42 against the inside contour of the mounting groove 1.

[0006] Because of the different thermal expansion behaviors between the blades, the rotor collar, and the rotor, a play is created during operation between the blades and the intermediate pieces inside the mounting groove, including the rotor collar. Because of the resulting circumferential play, the collar halves may shift in relation to one another in a circumferential direction along the mounting groove so that the spread wedge element is able to detach itself from the heart-shaped recesses. Such a case would again result in the initially described damage scenario.

SUMMARY OF THE INVENTION

[0007] The invention provides a device for fixing the blades in a turbo machine in such a way that the previously described damage scenario can be excluded.

[0008] According to the invention, a device for fixing blades is constructed in such a way that the wedge element is provided with at least one connecting element facing towards the side of a blade, and at least one of the two blades adjoining the wedge element is provided with a mating recess corresponding to the connecting element. The mating recess can preferably be provided with a corresponding shape to the shape of the connecting element, so that the wedge element and the blade enter into an intimate mated connection with each other.

[0009] The invention provides an intimate shape-mated connection between the wedge element and at least one immediately adjacent rotating blade, so that no relative movements between the rotating blade and the wedge element and, related to this, the entire rotor collar are able to occur, so that the initially described risk potential with respect to the detachment of the wedge element can be decisively limited.

[0010] In an especially advantageous manner, the wedge element is connected with the two immediately adjacent blades via respective shape-mating connecting elements. Such a design of a fixation device according to the invention is explained below in reference to the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The invention is described below as an example, using exemplary embodiments in reference to the drawings without limiting the general idea of the invention.

[0012]FIG. 1a shows a top view of a rotor collar according to the invention in connection with two adjacent blades.

[0013]FIG. 1b shows a top exploded view of the individual components illustrated in FIG. 1a.

[0014]FIG. 1c shows a side view of the rotor collar constructed according to the invention.

[0015]FIGS. 2a-c show illustrations of a conventional rotor collar.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016]FIG. 1a shows a top view of an assembly that includes two rotating blades 31, 32 inserted within a mounting groove (not shown) and a rotor collar 4 between the rotating blades 31, 32. The rotor collar 4 has a wedge element 43 that has on its sides facing the rotating blades 31, 32 one each connecting element 45 that is constructed as a dovetail. The connecting elements each engage with a mating recess 46 worked within the rotating blades 31,32.

[0017] As a result of the mechanical connection positioned according to the invention between the rotor collar 4 and the two rotating blades 31, 32, relative movements caused by different thermal expansion phenomena can be excluded. Accordingly, no impermissible gap is able to form along the mounting groove, which gap would result in the risk of a detachment of parts located inside the mounting groove.

[0018] The individual components illustrated in the exploded view of FIG. 1b clearly show the mating recesses 46 inside the rotating blades 31, 32. For the mounting of the rotor collar 4 constructed according to the invention, first the collar halves 41, 42 are inserted in a radial direction into the gap between the rotating blades 31, 32 in the mounting groove. Then, the wedge element 43 constructed according to the invention is also radially inserted both into the gap between the two collar halves 41, 42 as well as radially inside the mating recesses 46 formed in facing surfaces of the rotating blades 31, 32. This causes the two adjacent rotating blades 31, 32 to be mechanically connected with each other via the wedge element 43. If the wedge element 43 is sunk completely between the collar halves 41, 42, the retention tabs 44 of the wedge element 43 are pressed by means of a suitable tool into the heart-shaped recesses 6.

[0019] In addition to the construction of the connecting element 45 as a dovetail, alternative connection profiles are also encompassed by the invention. For example, the connecting elements 45 and mating recesses 46 could have hammer profiles of all types as well as Christmas tree profiles. It is preferred that the mating recess 46 is placed inside the blade root of the individual rotating blades 31, 32. The mating recess 46 need not necessarily extend over the entire depth of the blade root.

[0020]FIG. 1c shows a lateral view of the rotor collar 4 constructed according to the invention. In contrast to the illustration according to FIG. 2b, the wedge element 43 is provided with the connecting element 45, which according to the invention can be constructed as a dovetail. In the embodiment in FIG. 1c the connecting element 45 extends over the entire length of the blade root. As in the case of FIG. 2b, the wedge element 43 has two retention tabs 44 that engage with the corresponding recess 6 inside the rotating blades 41,42.

[0021] Alternative embodiments can include further connecting elements provided between the individual collar halves 41, 42 and the rotating blades 31, 32 immediately adjoining them. In this manner, a further improved, mechanically intimate connection can be achieved between the rotor collar constructed according to the invention and the adjacent rotating blades.

[0022] Connecting elements according to the invention can also be installed at a different place in the same blade row. 

1. Fixation device for blading of a turbo-machine, in which, longitudinally to a mounting groove (1), a plurality of blades (31, 32) is positioned, and in which, between at least two blades (31, 32) positioned adjacent to each other inside the mounting groove (1), a mounting gap is provided, having two insertion elements constructed as collar halves (41, 42) that can be inserted into the mounting gap, and each of which has a width adapted to the width of the mounting gap and which enclose between themselves a gap space (5) into which a wedge element (43) can be inserted that can be wedged in such a way that both collar halves (41, 42) are fixed in a force-derived manner by means of the wedge element (43) inside the mounting groove (1), characterized in that the wedge element (43) is provided with at least one connecting element (45) towards the side of a blade (31, 32) and that at least one of the two blades (31, 32) adjoining the wedge element (43) is provided with a counter-contour (46) corresponding to the connecting element (45), so that the wedge element (43) and the blade (31, 32) enter into an intimate shape-mated connection with each other.
 2. Fixation device according to claim 1, characterized in that the connecting element (45) and the corresponding counter-contour (46) are constructed as a dovetail connection.
 3. Fixation device according to claim 1 or 2, characterized in that the wedge element (43) is provided on both sides for both adjacent blades (31, 32) with connecting elements (45) in order to produce in each case a shape-mated connection.
 4. Fixation device according to one of claims 1 to 3, characterized in that the wedge element (43) can be pushed in radially between both blades (31, 32) and both collar halves (41, 42) and is provided with retention tabs (44) that can be permanently spread into recesses (6) provided correspondingly in the collar halves (41, 42).
 5. Fixation device according to one of claims 1 to 4, characterized in that at least one connecting element (45) as well as the corresponding counter-contour (46) are constructed as a hammer profile or in Christmas tree shape.
 6. Fixation device according to one of claims 1 to 5, characterized in that the blades (31, 32) are rotating blades inside a rotor arrangement or guide blades inside a stator arrangement.
 7. Fixation device according to one of claims 1 to 6, characterized in that the turbo-machine is a compressor unit or a turbine stage in a gas turbine system.
 8. Fixation device according to one of claims 1 to 7, characterized in that the blades (31, 32) are arranged in a row of blades and that at least one shape-mated connection is provided in the row of blades between the wedge element (43) and a blade (31, 32).
 9. Fixation device according to one of claims 1 to 9, characterized in that the blades (31, 32) of a row of blades are fixed in a mounting groove (1). 